Besides a general method by which a cast product is produced by sand mold casting, there has been proposed a method by which a cast product having excellent size accuracy is produced by casting. For example, an investment casting method (also referred to as a lost wax method), a plaster pattern casting method, a lost foam casting method and the like have been developed.
The lost foam casting method is a method for casting a cast product where a pattern is prepared by applying a refractory coating by coating to a surface of a foamed mold, the pattern is embedded into casting sand and, thereafter, molten metal is poured into the inside of the pattern, and the foamed mold is replaced with the molten metal by burning out the foamed mold.
JP 2011-110577 A discloses a lost foam casting method where a casting time at the time of casting is set corresponding to a modulus of the mold (a volume of the mold÷a surface area of the mold).